The present invention relates to an optical disc apparatus or a driving method of the optical disc apparatus.
As the document relating to the optical disc apparatus is published Patent Document 1. In that Patent Document 1, for example, in the abstract thereof is described “An optical disc apparatus is an apparatus of irradiates a light beam upon an information surface of a disc 1, upon the surface of which a light transmission layer is coated, and thereby conducing recording/reproducing. The optical sic apparatus comprises a sphere aberration controller portion 21 for correcting the sphere aberration generating on the light beam, in advance, a focus error detector portion 10 for detecting a focus error signal, and a controller 17 for adjusting a volume of the sphere aberration so that an amplitude of a signal of the focus error detector portion 10 has a predetermined value, after brining it to a predetermined volume with using the sphere aberration controller portion 21.” Also, in a column number 0015 of that document, there are described, “For a multi-layer disc having two or more pieces of information surfaces laminated thereon, it is preferable to be so constructed that a compensation can be made on the sphere aberration or a coma aberration, for each layer, by means of an aberration compensator means” and “It is preferable that the aberration compensator means compensate the sphere aberration or the coma aberration in advance when the apparatus starts, so that the amplitude of the signal of the detector means comes to the maximum, approximately.” And, with the optical disc apparatus described in that document, it is described that “An automatic amplitude control for maintaining a stable focusing and/or tracking characteristic(s) can be maintained, always, even when the sphere aberration and/or the coma aberration generate(s)” (in the abstract).
<Prior Art Documents>
<Patent Documents>
[Patent Document 1] Japanese Patent Laying-Open No. 2005-332558 (2005).
Within the optical disc apparatus, a laser beam, which is irradiated from an optical pickup directing to an optical disc, and also a reflection light from the optical disc are received upon the optical pickup, and thereby conducting recording/reproducing. According to a main regulation for the optical disc, a recording capacity increases in an order, such as, CD, DVD and BD, for example, and in particular, with DVD and BD, it has two (2) layer structures, e.g., recording/reproducing layers for increasing the recording capacity thereof, within the same disc. For the purpose of increasing the recording capacity, it becomes important with how much high accuracy the above-mentioned laser/reflection lights can be emitted/received, and recording/reproducing control thereupon can be executed upon basis of that signal. In particular, for the BD, a sphere aberration compensation mechanism is necessary as an optical compensation mechanism within an optical pickup, for the purpose of maintaining an accuracy of light emitting/receiving due to the sphere aberration. For the purpose of further increasing the memory capacity, it can be achieved by increasing a number of recording/reproducing layers, but there is necessity of a light emitting/receiving technology with high accuracy from a viewpoint of a S/N (Signal to Noise) of signal.
However, with the conventional technology, it takes a long time to adjust the signal in case of the optical disc having two (2) or more of the recording/reproducing layers, and there is remained a drawback from a viewpoint of usability for a user. For example, among processes included in an adjustment process, a process for compensating the sphere aberration takes a long time. In case when conducting the adjustment process, in particular, after compensating the sphere aberration for all of the layers, for example, a possibility that a number of times of conducting the sphere aberration comes to be large than a number of layers of the optical disc is high, and there is a passivity that it is impossible to reduce or shorten the time of the adjustment process. Also, such problem comes to be remarkable, as the number of layers of the optical disc increases.